Sodium nitrate



Nov. 26, 1935. w. STRATHMEYER 2,021,927

l' l soDIUM NITRATE Filed July 29, 1932 Patented Nov. 26, 1935 PATENT OFFICE soDIUM NITRATE Walter Strathmeyer, Oppau, Germany, assignor to I. G. Farbenindustrie Aktiengesellschaft, Frankfort-on-the-Main, Germany Application July 29, 1932, Serial No. 625,662' In Germany August 5, 1931 7 Claims. (Cl. 23--239) The present invention relates to sodium nitrate which is improved in its capacity for being stored and scattered and to a process for making such product.

The object of this invention is a process for producing sodium nitrate in globular granules having improved mechanical strength and the product of that process.

It has already been proposed, in order to improve the capacity of sodium nitrate for being stored and scattered, to melt it and spray it, for example according to the British Patent No. 315,262. In this manner globular granules are obtained which, however, have hollow spaces in the interior and the mechanical strength of which is consequently but slight, so that when stored in large amounts and when transported the globules collapse and thus lose their globular character. The advantages with regard to the desired properties in storing and scattering, which are produced by giving the salt the said form are thereby lost. In particular, the dust fraction, which has a very unfavorable eiect both on the capacity for storage and the capacity for being scattered, is considerably increased by the destruction of the globular shape of the granules.

On the other hand, it is known that sodium nitrate has often been marketed in a form containing a substantial proportion of other salts, as for example potassium nitrate. It has also been proposed to prepare mixed fertilizers from sodium nitrate'by mixing the same with other fertilizing salts, such as potassium chloride or potassium nitrate. However, products of the said kind which contain sodium nitrate and in addition thereto more or less substantial amounts of one or more other salts have never been marketed in the form of more or less globular granules.

I have now found that the mechanical strength of sprayed sodium nitrate is considerably increased and the disadvantages inherent in the sprayed products referred to above are therefore avoided by adding to the sodium nitrate, before the spraying, substances which increase the strength of the sprayed particles and which do not, or not appreciably, alter and in particular, not reduce, the nitrogen content of the sodium nitrate. Thus in accordancewith the present invention, there are used as addition substances materials containing nitrogen, namely nitrates or ammonium salts, especially those which have approximately the same nitrogen content as sodium nitrate. Of these, ammonium sulphate and potassium nitrate are especially suitable. Other salts containing nitrogen, such as magnesium nitrate, ammonium nitrate and iron nitrate, also 'increase the strength of the sprayed sodium nitrate.

The annexed drawingshows by way of illustration, on an enlarged scale, single grains of ex- V5'- amples of the type of product of this invention,

tween 1.5 and 12 per cent, and preferably between 3 and 5 per cent, are suicient to increase the pressure requiredA to destroy the granules of 2o the sprayed product by from two to seven times. In most cases amounts of less than 10 per cent will be employed.

i For the purpose of comparison with the products obtained according to the following examples, 25 sodium nitrate was melted without any additional substances and sprayed through a nozzle having an internal diameter of l millimeter. From the sprayed product, 10 globules were picked out having a diameter of 2.2 millimeters and the 30 pressure required to destroy them was determined. The average destroying pressure amounts to 350 grams. 'Ihe products described in the examples were tested in the same manner. The proportions given in the examples are given 35 in parts by weight.

Example 1 instead of the magnesium nitrate in Example 1, the destroying pressure under the same conditions amounts to 1080 grams.

Example 3 By employing 3 parts of potassium nitrate instead of the magnesium nitrate in Example 1,

a destroying pressure of 1800 grams is attained and a product of the type illustrated in Fig. 1 is obtained.

Example 4 the following pour weights i. e. the weight of the product which occupies a given volume after pouring:-

The pour weight with sodium nitrate without any additional substances is 1150 grams per liter. The pour weights of sodium nitrate each with 3 per cent of additional substances are given in the following tablez- Additional substance Pour weight Grams per liter Magnesium nitrate 1180 Ammonium nitrate 1190 Potassium nitrate--. 1200 Ammonium sulphate. 1220 Example 5 95 parts of sodium nitrate are fused with an addition of 5 parts of magnesium nitrate and sprayed as already described. The average destying pressure of 10 globules having a diameter of 2.2 millimeters is 1400 grams.

Ewmple '6' parts of sodium nitrate are fused with an addition of 10 parts of magnesium nitrate and sprayed as already described. vThe average destroying pressure of 10 globules having a diameter of 2.2 millimeters is 1800 grams.

What I claim is:

1. Sodium nitrate in the form o-f substantially globular rounded grains substantially free from voids and containing between 1.5 and 12 per cent of an inorganic nitrogenous fertilizing salt selected from the group consisting of ammonium salts and those nitrates which are different from sodium nitrate.

2. Sodium nitrate in the form of substantially globular rounded grains substantially free from voids and containing between 3 and 5 per cent .globular rounded grains Ysubstantially free from voidsand containing between 3 and 5 per cent of ammonium sulphate.

6. The process of producing sodium nitrate of improved storage properties from practically pure sodium nitrate which comprises spray-solidifying the sodium nitrate from the fused state after having incorporated therewith between 1.5 and 12 per cent of an inorganic nitrogenous fertilizing salt selected from the group consisting of ammoniumsalts and those nitrates which are different from sodium nitrate.

'7. The process of producing sodium nitrate of improved storage properties from practically pure sodium nitrate which comprises spraysolidifying the sodium'nitrate from the fused state after having incorporated therewith between 3 and 5 per cent of an inorganic nitrogenous fertilizing salt selected from the group consisting of ammonium salts and those nitrates which are different from sodium nitrate.

WALTER STRATHMEYER. 

